# All online calculators

- Distance and midpoint between two points
This online calculator find distance and midpoint between two points in cartesian coordinates.

- Distance between two cities
Calculates the distance between the two cities. Uses the directory of geographical city coordinates for the calculation.

- Distance calculator
Calculates distance between two geographic coordinates using haversine formula.

- Distance through the Earth
This calculator calculates the distance from one point on the Earth to another point, going through the Earth, instead of going across the surface.

- Dollars to rubles and vice versa by Central Bank of Russia exchange rate
- Doppler Effect in sound
Calculation of frequency and wavelength change for a moving source

- Dot product
This online calculator calculates the dot product of two vectors

- Double exponential smoothing
Description and example of the double exponential smoothing

- Earth Radius by Latitude (WGS 84)
This online calculator calculates Earth radius at given latitude using WGS 84 reference ellipsoid

- Effective interest rate
- Eigenvalue calculator
This online calculator computes the eigenvalues of a square matrix up to 4th degree by solving the characteristic equation.

- Ellipsoid
Calculates ellipsoid and spheroid volume and surface area.

- Email extractor
This online calculator parses emails from block of text using regular expression

- Energy measurement units
Energy unit converter (joules, kilowatt-hour, kilogram force per meter, horsepower per hour, kilocalories)

- Equation of a circle passing through 3 given points
This online calculator finds equation of a circle passing through 3 given points

- Equation of a line passing through two points in 3d
This online calculator finds equation of a line in parametrical and symmetrical forms given coordinates of two points on the line

- Equation of a plane passing through three points
This online calculator calculates the general form of the equation of a plane passing through three points

- Equations of a circle with given center and radius in different forms
This online calculator displays equations of a circle in standard form, in parametric form and in general form given center and radius of a circle

- Equilateral triangle
This online calculator calculates characteristics of the equilateral triangle: the length of the sides, the area, the perimeter, the radius of the circumscribed circle, the radius of the inscribed circle, the altitude (height) from single known value

- Equilibrium moisture content
The calculator gives the wood equilibrium moisture content by given temperature and relative humidity.